The invention relates to a hot-rolled concrete reinforcing bar, in particular a reinforcing ribbed bar.
Concrete reinforcing bars of this type are described for example in Beton- und Stahlbetonbau 2/1973, pages 25 to 35.
In screwable concrete reinforcing bars the ribs perform a double purpose. Firstly, they must ensure adequate bond in the concrete and secondly in their function as parts of a thread be able to transmit the necessary forces into an anchoring or connecting body into which an end of the concrete reinforcing bar is screwed.
With regard to these two functions in practice the concrete reinforcing bars known as GEWI-steel (registered trademark) have established themselves and are described in the aforementioned journal.
These concrete reinforcing bars have ribs relatively wide with respect to the bar diameter with relatively small spacing. The ratio of foot width of the rib to rib height of the reinforcing steel is about 3.7 and the rib spacing measured in the longitudinal direction is about 0.5 with respect to the nominal diameter. This corresponds to an inclination angle .alpha. of the ribs to the longitudinal axis of the concrete reinforcing bar of about 81.5.degree..
Because of this rib form and rib arrangement short thread connections are possible and due to the relatively large inclination angle .alpha. of the ribs to the longitudinal axis of the concrete reinforcing bar self-locking of the thread connection is ensured.